I'm writing an article to a conference. The subject is usefulness of international SIMs in reduction of international roaming costs. I focus mainly on free incoming calls feature and the Polish point of view (i.e. international SIMs vs Polish roaming tariffs).
I'm going to consider the following SIMs:
UM 423/ICQSIM
UM+
Geosim
Travelsim
09
Telestial Passport

The features which I took into account when creating the list were:
1) Free incoming calls in Poland and some other countries (the more the better of course)
2) Possibility of purchasing the SIM online and sending it to a Polish address
3) The calling party doesn't pay for unaswered/busy calls to an international SIM (of course, if not forwarded to VM or elsewhere)
4) The possibility of disabling the VM.

Do you think that I should consider any other SIMs (as of April 200?

And another questions - "historical" ones .

The first international SIM with free incoming calls was Riiing that appeared on the market in autumn 2004, right?
By checking web.archive.org I found that Hop appeared in 2002.
What about other pre-2005 international SIMs? From the forum I remember brands Swisscom Easyroam and MINT. What years where they available and were they the same? Were there any other "ancient" brands?

I think the offer by Swiss GSM was the very first one, but surely not cheap and without free incoming calls (except in CH, of course). Then I think Hop Mobile was the first real International card, not connected to a local opertor. But once again no free incoming calls. More or less at the same time also United Mobile started, it was cheaper than Hop (also because at that time € was lower than $) and had no free incoming calls.

The first offer with free incoming calls was Riiing, still ownded by United Mobile, but with a different brand. I cannot remember if it was Autumn 2004.
Then 09 started, then Travelsim and at last all the IoM based simcards.

One other thing you might consider is the number attached to the sims.

Ihave a UM and UM+ but in the past I had complaints thaty some of my customers could not reacht the UM lichtenstein number or as you know calling Lichtenstein mobile is expensive these days.

09 is iceland and for example Yackie uses that platform. Here again the same problems calling a iceland mobile number is very difficult, some voip providers don't even connect of the rate is high.

I would think that besides the importance of free incoming it's also important which number is attached to the card and if anyone can reach that number.
When giving out the number you always have people asking questions about the number and explaining why you have a lichtenstein or iceland number. Therefore a +44 based mobile number with free incoming is the perfect solution.

I think you might also include the German ones, especially if some appear with other country numbers on them.

Also, the various SIMs with forwarded local landline DIDs, such as Celtrek Maxroam & Yackie, which are roughly in the same cost range but don't require the customer to set up their own forwarding arrangements or make people calling them incur international rates.

... which could lead you into explaining how people willing to make their own forwarding arrangements can do so.